1. Field
The present disclosure relates to a solid ion conductor with high ionic conductivity, a solid electrolyte including the solid ion conductor, a lithium battery including the solid electrolyte, and a method of manufacturing the solid ion conductor.
2. Description of the Related Art
Lithium batteries have high voltage and energy density, and are used in various fields. For example, in electric vehicles, hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs), battery operation at high temperatures, charging or discharging a large amount of electricity, and a long period of battery use can be desirable.
In a lithium battery including a liquid electrolyte, i.e., an electrolyte prepared by dissolving a lithium salt in an organic solvent, the liquid electrolyte starts to decompose at a voltage of 2.5 V or more. Also, the liquid electrolyte has a high risk of leakage, fire, and explosion. Further, the liquid electrolyte can support the formation of dendrites, which can cause self-discharging and heating of a lithium battery.
An all-solid-state lithium battery including a lithium ion conductor as a solid electrolyte can have a higher stability than that of a lithium battery including a liquid electrolyte. The lithium ion conductor constituting the solid electrolyte is a single ion conductor in which only Li ions are migrated, and thus it has no risk of ignition, as compared to lithium batteries including a liquid electrolyte. Therefore, all-solid-state lithium batteries are suitable for use in electric vehicles, large-scale storage batteries, and the like.
The solid ion conductor desirably has high lithium ion conductivity, is chemically stable, and has a wide potential window, for use as a solid electrolyte for a lithium battery.
A garnet-type oxide, such as Li5La3M2O12 (M=Nb or Ta), is chemically stable and has a wide potential window, while it has a poor lithium ionic conductivity (e.g., approximately ˜10−6 Siemens per centimeter (S/cm)) at 25° C.